.nav-header {
    position: fixed;
    left: 0;
    top: 0;
    height: 100px;
    z-index: 1000;
    width: 100%;
    box-sizing: border-box;
    text-align: center;
    line-height: 100px;
    background-color: #2a2a2a;
    font-size: 50px;
    color: #fff;
    .anticon-left {
      position: absolute;
      left: 20px;
      line-height: 100px;
      
    }
  }